You should generate the Lost Media Report regularly so you can recall media that has not been returned from the offsite vault vendor but which should have been returned.
Media can get stranded at the offsite vault for the following reasons:
Frozen backup tapes never expire. A backup tape that does not expire does not appear on the Picking List for Vault and is not be recalled from the vault.
A backup tape appears on the Picking List for Vault and Distribution List for Robot only once. If a tape from that report is missed and is not returned to the robot, it never again is listed for recall.
You change offsite volume group or pool names. For example, if you begin to use a new media type, you have to use a new volume pool name. If you change names, media may be stranded offsite because the Picking List for Vault is based on offsite volume pools and offsite volume groups. Media associated with the old names is not be listed.
Symantec recommends that you do not change or rename group or pool names.
How often you generate the Lost Media Report depends on your operations. Weekly or monthly may be often enough.
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